Yeast dough that rises before being baked must stand for a period of time while yeast acts to decompose sugar. The decomposition of sugar generates carbon dioxide which produces the bubbles or open spaces within the dough which ultimately give the baked product its texture. Frequently the dough must be knocked down after it rises and permitted to rise again, perhaps several times before the dough is finally ready to bake.
The rising process is very sensitive to ambient conditions. It should take place at a temperature in the range of 75-90 degrees F. and in an environment that is fairly humid. The environment in which the dough riser should also have uniform conditions throughout.
Particularly dough should rise away from drafts which may cool the environment generally or cause one portion of the body of dough to be cooler than other portions. Bread having good and uniform texture requires careful attention to the environment in which the dough rises.
The dough for bread baked at home typically is placed in a baking pan or a bowl which is covered with a cloth which in turn is placed in a warm environment such as in a bowl of hot water, near a heating vent or in an oven. The ambient conditions in the kitchen of an ordinary home will vary from season to season, from day to day and even from day to night so that skill is required to produce uniform conditions in which the dough rises.
Environmental chambers to create the correct conditions for dough to rise are known. Mostly, these environmental chambers are in the form of boxes and many are equipped with controls for temperature and humidity. However, in an ordinary, home kitchen it is important to conserve storage space and it is very desirable for a baking implement such as an environmental chamber to consume a small amount of space when it is stored. Collapsible chambers which occupy a small volume when stored but expand to enclose a large volume when in use are known. Some of these prior collapsible chambers employ an umbrella-like structure and others are supported by legs or ribs that fold. Weiss U.S. Pat. No. 4,210,073 discloses one such environmental chamber which comprises ribs or legs that support panels of flexible, foldable material that can be stretched over the ribs or legs to form an enclosed chamber but can be folded between them when the chamber is collapsed. A problem with a collapsible chamber such as disclosed in the Weiss patent is that when it is standing on a support surface, such as a tabletop or a work counter, the tightly stretched fabric or other foldable material between adjacent legs creates a space between the support surface and the lowest extremity of the foldable, flexible material forming the panel. FIG. 2 of the Weiss patent exemplifies the problem of permitting drafts to enter the environment control chamber in this way. Thus, it is desirable for home use to have a collapsible environmental chamber that can maintain an elevated temperature environment within it and which fits tightly enough against a support surface to exclude drafts from its interior.